In deblet the usb networking driver is loaded by default to support telnet over usb.
Try these commands as root in deblet:
killall utelnetd
ifconfig down usb0
rmmod g_ether
modprobe g_file_storage stall=0 luns=2 removable
echo host > /sys/class/usb_host/usb_host1/device/mode

If those work, add them into rc.local (above exit 0) and run:
chmod +x /etc/rc.local

-John